Techniques to Screen for Resistance to Insects

Sorghum shoot fly (Atherigona soccata), stem borers (Chilo, Busseola, and Diatraea), midge (Stenodiplosis sorghicola) and head bugs (Calocoris

angustatus and Eurystylus oldi) in sorghum; stem borer (Coniesta ignefusalis) and head miner (Heliocheilus albipunctella) in pearl millet; pod borer

(Helicoverpa armigera) in chickpea and pigeonpea; and leaf miner (Apraorema modicella) and tobacco caterpillar (Spodoptera litura) in groundnut are the

most important pests of cereals and grain legumes in the semi-arid tropics (SAT).

Insect pests cause an estimated loss of over US$10 billion annually in the SAT. Since insecticide application is uneconomic under subsistence farming, it is

important to develop cultivars with resistance to insects. To achieve these objectives, we have standardized several techniques to screen and select for

resistance to insect pests in ICRISAT mandate crops.

Infester row technique to

screen for resistance to

sorghum midge.

A B

Cage technique to screen for resistance to shoot fly (A), midge (B), and

head bugs (C) in sorghum; and no-choice cage (D) techniques to screen

for resistance to Helicoverpa and Spodoptera in chickpea, pigeonpea and

groundnut.

These resistance screening techniques are being used to evaluate

germplasm, segregating breeding lines, mapping populations, and

transgenic plants for resistance to insect pests world wide.

C D

Detached leaf assay to screen for resistance to Helicoverpa and

Spodoptera in chickpea, pigeonpea, cotton and groundnut.

A B

Interlard fishmeal technique to screen for resistance to shoot fly. Artificial infestation technique to screen for resistance to stem borer.

Use of hot spot locations to screen for

resistance to Helicoverpa.

ICRISAT is a member of the CGIAR Consortium

HC Sharma, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Telangana, India. Email: h.sharma@cgiar.org